In a letter obtained Wednesday by The Associated Press, Haley tells Energy Secretary Ernest Moniz to stop or reroute a shipment of 331 kilograms of plutonium coming to the Savannah River Site from Japan.

Tons of plutonium have accumulated over the years at the former nuclear weapons complex, where a facility to process such materials into commercial nuclear reactor fuel remains incomplete.

South Carolina is already suing the federal government over what Haley has called its broken promise to the state to finish the mixed-oxide fuel facility, The lawsuit seeks daily fines of $1 million and removal of the plutonium.